Conventionally, a facsimile apparatus which can read images on both sides of an original document and transmit the obtained images is known. In this kind of facsimile apparatus, a transmitter side designates both-side transmission via an NSS/DCS (Nonstandard Facilities Setup/Digital Command Signal) signal or the like, whereby the both-side transmission is thus designated. Then, when image data of a both-side original document is transmitted, images on the front and back sides of respective pages are sequentially encoded and transmitted in the order of the front side of the first page, the back side of the first page, the front side of the second page, the back side of the second page, the front side of the n-th page, and the back side of the n-th page. In the real transmission, the data on the front side and the data on the back side are transmitted and received according to the same procedure as that for one page in conventional one-side transmission.
According to the above conventional example, the information on both the sides of the transmission original document can be surely transmitted. However, in such a conventional structure as described above, in a case where the both-side original document and a one-side original document (such as the original document of which only the front side includes image data but the back side is blank) are mixedly present, the image data of the one side (the front or back side of the one-side original document) not including any available data must be transmitted as well as the image data on the side including available data, there is a problem that communication expense necessary for such the transmission of the image data on the side not including any available data is wasted.
Although a data amount of the blank side is not so large if compression transmission is adopted, since the information on the front and back sides is transmitted and received according to the procedure same as that of one page in the one-side transmission, there is a problem that a needless communication time is spent by an inter-page procedure.
The substance of the present invention is to solve the above problems, to be able to shorten the communication time for the both-side transmission in a case where the original document includes such the information of the one side as being blank, and further to be able to perform, on a reception side, both-side recording intended by a transmission side even if the order of pages to be transmitted is changed or even if the front and/or back sides of the original document are took out and put in.